The association of optical packet transmission with polarization division multiplexing (PDM) is receiving attention for the development of high data-rate, highly flexible communication systems. Coherent receivers have been originally designed for optical circuit connections. The convergence time of a conventional polarization demultiplexing algorithm takes typically a few thousand symbols. In packet transmission, every packet has its own state of polarization (SOP). Repeating the conventional convergence process for each and every packet would consume a large amount of the bandwidth.
EP-A-2273700 teaches methods for speeding up convergence of a polarization demultiplexing filter in a coherent receiver adapted to optical packet reception. These methods involve the generation of optical packets comprising a header section including a single-polarization optical signal and a payload section including a polarization division multiplexed optical signal. To generate such an optical packet, EP-A-2273700 teaches methods that require turning on and off the drivers of MZ modulators and changing the bias of Mach-Zehnder (MZ) modulators at a very high speed between the header section and payload section.